<?php namespace CodeIgniter\Cache\Handlers;

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	CodeIgniter Dev Team
 * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	https://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 3.0.0
 * @filesource
 */

use CodeIgniter\Cache\CacheInterface;
use CodeIgniter\CriticalError;

class PredisHandler implements CacheInterface
{
	/**
	 * Prefixed to all cache names.
	 *
	 * @var string
	 */
	protected $prefix;

	/**
	 * Default config
	 *
	 * @static
	 * @var    array
	 */
	protected $config = [
		'scheme'   => 'tcp',
		'host'     => '127.0.0.1',
		'password' => null,
		'port'     => 6379,
		'timeout'  => 0,
	];

	/**
	 * Predis connection
	 *
	 * @var    Predis
	 */
	protected $redis;

	//--------------------------------------------------------------------

	public function __construct($config)
	{
		$this->prefix = $config->prefix ?: '';

		if (isset($config->redis))
		{
			$this->config = array_merge($this->config, $config->redis);
		}
	}

	//--------------------------------------------------------------------

	/**
	 * Takes care of any handler-specific setup that must be done.
	 */
	public function initialize()
	{
		try
		{
			// Create a new instance of Predis\Client
			$this->redis = new \Predis\Client($this->config, ['prefix' => $this->prefix]);

			// Check if the connection is valid by trying to get the time.
			$this->redis->time();
		}
		catch (Exception $e)
		{
			// thrown if can't connect to redis server.
			throw new CriticalError('Cache: Predis connection refused ('.$e->getMessage().')');
					}
					}

					//--------------------------------------------------------------------

					/**
					 * Attempts to fetch an item from the cache store.
					 *
					 * @param string $key Cache item name
					 *
					 * @return mixed
					 */
					public function get(string $key)
					{
					$data = array_combine(
							['__ci_type', '__ci_value'],
							$this->redis->hmget($key, ['__ci_type', '__ci_value'])
							);

					if (! isset($data['__ci_type'], $data['__ci_value']) OR $data['__ci_value'] === false)
					{
						return false;
					}

					switch ($data['__ci_type'])
					{
						case 'array':
						case 'object':
							return unserialize($data['__ci_value']);
						case 'boolean':
						case 'integer':
						case 'double': // Yes, 'double' is returned and NOT 'float'
						case 'string':
						case 'NULL':
							return settype($data['__ci_value'], $data['__ci_type'])
								? $data['__ci_value']
								: false;
						case 'resource':
						default:
							return false;
					}
					}

			//--------------------------------------------------------------------

			/**
			 * Saves an item to the cache store.
			 *
			 * The $raw parameter is only utilized by predis in order to
			 * allow usage of increment() and decrement().
			 *
			 * @param string $key    Cache item name
			 * @param        $value  the data to save
			 * @param null   $ttl    Time To Live, in seconds (default 60)
			 * @param bool   $raw    Whether to store the raw value.
			 *
			 * @return mixed
			 */
			public function save(string $key, $value, int $ttl = 60, bool $raw = false)
			{
				switch ($data_type = gettype($value))
				{
					case 'array':
					case 'object':
						$value = serialize($value);
						break;
					case 'boolean':
					case 'integer':
					case 'double': // Yes, 'double' is returned and NOT 'float'
					case 'string':
					case 'NULL':
						break;
					case 'resource':
					default:
						return false;
				}

				if (! $this->redis->hmset($key, ['__ci_type' => $data_type, '__ci_value' => $value]))
				{
					return false;
				}

				$this->redis->expireat($key, time()+$ttl);

				return true;
			}

			//--------------------------------------------------------------------

			/**
			 * Deletes a specific item from the cache store.
			 *
			 * @param string $key Cache item name
			 *
			 * @return mixed
			 */
			public function delete(string $key)
			{
				return ($this->redis->del($key) === 1);
			}

			//--------------------------------------------------------------------

			/**
			 * Performs atomic incrementation of a raw stored value.
			 *
			 * @param string $key    Cache ID
			 * @param int    $offset Step/value to increase by
			 *
			 * @return mixed
			 */
			public function increment(string $key, int $offset = 1)
			{
				return $this->redis->hincrby($key, 'data', $offset);
			}

			//--------------------------------------------------------------------

			/**
			 * Performs atomic decrementation of a raw stored value.
			 *
			 * @param string $key    Cache ID
			 * @param int    $offset Step/value to increase by
			 *
			 * @return mixed
			 */
			public function decrement(string $key, int $offset = 1)
			{
				return $this->redis->hincrby($key, 'data', -$offset);
			}

			//--------------------------------------------------------------------

			/**
			 * Will delete all items in the entire cache.
			 *
			 * @return mixed
			 */
			public function clean()
			{
				return $this->redis->flushdb();
			}

			//--------------------------------------------------------------------

			/**
			 * Returns information on the entire cache.
			 *
			 * The information returned and the structure of the data
			 * varies depending on the handler.
			 *
			 * @return mixed
			 */
			public function getCacheInfo()
			{
				return $this->redis->info();
			}

			//--------------------------------------------------------------------

			/**
			 * Returns detailed information about the specific item in the cache.
			 *
			 * @param string $key Cache item name.
			 *
			 * @return mixed
			 */
			public function getMetaData(string $key)
			{
				$data = array_combine(['__ci_value'], $this->redis->hmget($key, ['__ci_value']));

				if (isset($data['__ci_value']) AND $data['__ci_value'] !== false)
				{
					return array(
							'expire' => time() + $this->redis->ttl($key),
							'data' => $data['__ci_value']
							);
				}

				return FALSE;
			}

			//--------------------------------------------------------------------

			/**
			 * Determines if the driver is supported on this system.
			 *
			 * @return boolean
			 */
			public function isSupported(): bool
	{
		return class_exists('\Predis\Client');
	}

			//--------------------------------------------------------------------

}
